There is no consensus on the treatment of patients with recurrent infections and isolated immunoglobulin G (IgG)-subclass deficiency and/or selective antipolysaccharide antibody deficiency. Therefore, the Dutch Inter University Working Party will start a study in which the treatment with antibiotics is compared with intravenous immunoglobulin therapy with respect to clinical outcome measures in both children and adults with this disorder.

There is no consensus on the treatment of patients with recurrent infections and isolated IgG-subclass deficiency and/or selective antipolysaccharide antibody deficiency. At present, there are no robust criteria to predict which patient will or will not respond adequately to antibiotic treatment or to IVIG. Furthermore, it is unknown whether IVIG treatment improves the quality of life in these patients. Therefore, the Dutch InterUniversity Working Party intends to start a study in this patient group. In this study, treatment for a year with antibiotics will be compared with a year intravenous immunoglobulin therapy with respect to clinical outcome measures in both children and adults with this disorder.

The patient will visit the clinic every 3 months during which laboratory tests and physiological measurements will be performed. Moreover the occurrence of infections and fever, the use of antibiotics, hospital admissions, and quality of life will be documented.

The study should result in a national harmonization in the treatment of this patient group. To this end, the results of the study will be used to compile a treatment protocol for this group of patients in the Netherlands and if applicable also in other countries worldwide.

Inclusion Criteria:

• IgG subclass deficiency and/or (selective) antipolysaccharide antibody deficiency
• At least 2 physician documented infections before the start of the current treatment or in the last 6 months for newly diagnosed patients.
• Total serum IgG > 4 g/l
• ≥ 5 years of age
• Informed consent

Exclusion Criteria:

• Treatment with any other investigational drug within 7 days prior to study entry, or previous enrolment in this study
• Allergic reactions against human plasma/plasma products, or co-trimoxazole
• An ongoing progressive terminal disease
• Pregnancy or lactation
• History of (transient) cerebrovascular accident or coronary insufficiency
• Renal insufficiency (plasma creatinin > 115 µmol/L; or creatinin clearance <20 ml/min)
• An ongoing active disease causing general symptoms e.g. chronic active hepatitis or persistent enterovirus infection with ongoing systemic complaints
• Detectable anti-IgA antibodies
• Active systemic lupus erythematosus (SLE)
• Glucose-6-phosphate hydrogenase deficiency